Axin cancer mutants form nanoaggregates to rewire the Wnt signaling network

Area of Science:

• Molecular biology
• Cell signaling
• Cancer research

Background:

• Scaffold proteins are crucial for organizing signaling complexes.
• Missense mutations in scaffold proteins are common in cancer but their roles are unclear.
• Axin is a key scaffold protein in Wnt signaling, and its mutations are implicated in cancer.

Purpose of the Study:

• To investigate the role of cancer-associated Axin mutations in Wnt signaling.
• To elucidate the mechanism by which mutated Axin promotes tumor growth.
• To explore therapeutic strategies targeting Axin mutations.

Main Methods:

• Analysis of cancer point mutations in Axin.
• In vivo studies in cancer models.
• Biochemical assays to study protein aggregation and interactome.
• Functional rescue experiments by preventing aggregation.

Main Results:

• Cancer point mutations in Axin lead to a gain-of-function mechanism that promotes tumor growth.
• Mutated Axin forms nonamyloid aggregates with disordered structures, altering its protein interactions.
• The tumor-suppressive activity of Axin mutants can be restored by inhibiting the aggregation of specific segments.
• These findings are conserved across human and Drosophila Axin proteins.

Conclusions:

• Cancer-derived Axin mutations represent a novel mechanism of signaling pathway misregulation.
• Axin aggregation is a key driver of tumor formation in these mutants.
• Targeting aggregation-prone regions in mutated scaffold proteins is a promising therapeutic avenue for cancer treatment.